Fire protection system for large airports



March 3, 1942. E. GEERTZ 2,274,784

FIRE PROTECTION SYSTEM FOR LARGE AIRPORTS Filed Dec. 28, 1959 2Sheets-Sheet 1 March 3, 1942.

E. GEERTZ FIRE PROTECTION SYSTEM FOR LARGE AIRPORTS Filed Dec. 28, 19392 Sheets-Sheet 2 Patented Mar. 3, 1942 FIRE PROTECTION SYSTEM FOR LARGEAIRPORTS Eric Geertz, Glen Ellyn, 111., assignor to Cardox Corporation,Chicago, 111., a corporation of 11- linois Application December 28,1939, Serial No. 311,430

21 Claims. (Cl. 169-11) This invention relates to new and usefulimprovements in methods and apparatus for providing fire protection forlarge commercial airports, or the like, including their hangars, shipsin and around the hangars, and activities on the runways and adjacentportions of the flying field.

Commercial airports, and other flying fields, present a particularlydifiicult fire hazard for any fire department to take care of. Thehazard usually involves two or more large hangars; a considerableinvestment in idle airplanes either being repaired or reserviced fortheir next run and valuable testing instruments and tools; gasoline andoil stored in the tanks of the idle airplanes; the location of theairport or field at the outskirts of a city where an adequatesupply ofwater is not always available; possibilities of crashes in the landingand taking oif of airplanes on the runways, etc. The hangars arerecognized as the most troublesome items of this type of hazard becauseof the concentration of so much highly inflammable material always to befound in and around each one of the same. A plane may crash on a runwayand be completely consumed by fire without involving any other object atthe airport or flying field. However, when a fire gains real headway ina hangar, the chances have been that the fire would spread throughoutthe remaining buildings, etc., of the airport or At most modern flyingfields, the hangars are positioned a reasonable distance from each otherto prevent as much as. possible the spreading of fire from one hangar tothe other. This precaution would be effective if a major fire involvingone hangar were extinguished in a reasonably short length of time.Previous attempts to combat such fires, where water has been used as theextinguishing medium, have not been very successful in confining thefire to one hangar because of:

(l) The ineffectiveness of water in combating fires involving gasolineand oil.

(2) The intensity of the fire.

(3) The concentration of the hottest portions of the fire at numerousscattered locations througout the large interior of the hangar. v

(4) The way in which airplanes housed within a hangar obstructorinterfere with attempts to reach all portions of the interior of thehangar with streams of water which are manipulated from thecomparatively few available entrances.

(5) The need for firemen to enter the hangar to lay hoselines to morestrategic points of attack if th fire cannot be extinguished from theavailable entrances.

(6) The great danger to which firemen entering the hangar must exposethemselves because of the likelihood of gas tank explosions and of theroof'falling due to buckling of the necessarily long roof rafters ortrusses which can only be supported on the side walls.

Airport and flying field operators have for a long time recognized thegreat value of liquid carbon dioxide as an extinguishing medium forfires involving airplanes, etc. They have been greatly handicapped inits use, however, because it has never been made available to them inany amounts greater than 50 pounds to a unit. This is due to the factthat liquid carbon dioxide has always been stored in cylinders which areleft exposed to changes in temperature of the surrounding air and thevapor pressure of the liquid in such cylinders is practically always inexcess of 1000 pounds per square inch. As a result, these operators haveonly been able to rely on this type of extinguishing medium forcombating small localized fires, and a few small cylinders, notexceeding 50 poundsinqcapacity, usually are found scattered around thehangars, etc.

It has been determined that the most effective way of extinguishing asizeable fire raging in an enclosed space is to totally flood the spacewith carbon dioxide vapors, i. e., discharge sufiicient carbon dioxidevapors into the space to provide a concentration of the same in allportions of the space which will put out the fire and cool all heatabsorbing objects below the kindling point of the combustible materials.This carbon dioxide concentration will vary with difierent combustiblematerials and different amounts of materials or masses to be cooled. A65% concentration will be sufiicient for all conditions and a 30%concentration will be ample for a large percentage of cases.

Large quantities of liquid carbon dioxide maintained in readiness forinstant use at a controlled subatmospheric temperature and itscorresponding low vapor pressure constitutes a part of the disclosure ofmy Patent No. 2,143,311, issued January 10, 1939. This low temperaturecarbon dioxide is an extremely effective fire extinguishing medium forlarge fires and appears to be the only available extinguishing mediumwhich, when handled in accordance with the aforesaid patented method,can be discharged in sufiiciently large quantities andat a sufficientlyrapid rate to successfully combat fires inyolving substantial amounts ofgasoline. and oil As all airplane hangars are designed to provide aslarge a single unobstructed enclosed space, with ample overheadclearance, as is possible, it requires a considerable amount of carbondioxide to flood one o; the same. Every modern flying field of any sizehas at least two hangars and there are several commercial airports inthis country which have three, four, five, or more. The total amount ofcarbon dioxide required to flood all of the hangars of an airport, whenseveral hangars are involved, reaches somewhat staggering proportions.

For example, one commercial airport now in operation in an eastern statehas four hangars, each of which would require 80 tons of carbon dioxideto flood the same. This amount of liquid carbon dioxide is ratherdifiicult to comprehend or visualize, but it is rendered less difiicultwhen one considers that railway tank cars have been employed fortransporting the low temperature and pressure liquid carbon dioxide ofmy aforementioned patent and that each one of these tank cars has a loadcapacity of 24 tons. Eighty tons of liquid carbon dioxide, therefore,would require a storage spacewhich would be the equivalent of three anda thirdrailway tank cars. If one were to provide 80 tons of liquidcarbon dioxide for each one of the four hangars of the above referred tocommercial airport, a total storage space of 320 ton capacity would beneeded and thirteen and a third railway tank cars would be theequivalent of such a storage space.

Of course, high pressure carbon dioxide has been employed to a limitedextent to protect hazards requiring up to from A9. ton to 1 ton. Thishigh pressure liquid carbon dioxide, however, has always been stored inbanks of interconnected cylinders with each cylinder having a maximumstorage capacity of 50 pounds. Naturally, a separate control valve mustbe provided for each one of such interconnected cylinders. Therefore, tomake available sufiicient high pressure liquid carbon dioxide to floodone of the aforesaid hangars would require the use of a bank of 3200cylinders and 3200 separate control valves. To simultaneously fiood allfour hangars would require 12,800 cylinders and the same number ofseparate control valves.

A sufficient amount of high pressure liquid carbon dioxide cannot bedischarged from 50 pound cylinders to flood a space as large as anaverage airplane hangar in a sufiiciently short length of time to beeffectively employed as a fire extinguishing medium because of thetremendous array of valves and manifold piping required to connect thislarge a numbe r of cylinders in a bank. It has been' determined,however, that low temperature, low pressure liquid carbon dioxide storedin a single tank of 4 tons capacity can be discharged at a rate of 100pounds a second through a single four inch pipe. Of course, much morerapid rates of discharge may be provided from'a single tank of largercapacity, if desired, by employing either more or larger dischargepipes.

gasoline and oil fires and reduces the oxygen concentration to such avalue that explosive mixtures of gasoline vapors and oxygen will notexist. It cools and extinguishes the hottest of fires. Its applicationto the interior of a hangar may be accomplished by means of a fixedpiping system which makes it unnecessary for firemen to enter the hangaruntil after the fire is completely extinguished. The most effectivepoint or zone of application of carbon dioxide vapors is adjacent theroof, because the vapors are more dense than air and will settledownwardly. As the vapors have subzero temperature, the release of thesame adjacent the roof will keep the rafters and trusses cool, and therewill be no danger of the roof falling.

It is the primary object of this invention to provide a system, ormethods and apparatus, which will make it possible and entirelypractical for commercial airports, or other flying fields, to be fullyprotected with carbon dioxide from fires occurring either in or aroundany of the hangars and on or around the runways.

A still further object of the invention is to provide a single systemwhich will make it possible for all of the hangars, the runways, and theareas adjacent them at any airport or fiying field to be adequatelyprotected from fire with a total amount of liquid carbon dioxide whichneed not materially exceed the amount required to totally flood thelargest one of the hangars.

Another object of the invention is to provide a fire protection systemof the above mentioned type which will maintain at each one of theseveral involved hangars a quantity of liquid carbon dioxide that willbe available for immediate discharge into the hangar to start thedesired flooding operation and which will be adequate to carry on thesaid operation until the remainder of the liquid carbon dioxide storedat the other hangars can be made available.

Other objects and advantages of the invention will be apparent duringthe course of the following description.

In the accompanying drawings forming a part of this specification and inwhich like numerals are employed to designate like parts throughout thesame,

Figure 1 is a diagrammatic view of a series of hangars and an associatedrunway with the fire protection system embodying this invention suitablyinstalled with respect thereto, and

Figure 2 is a detail, elevational view, partly broken away, illustratingthe installation ofthe envelope every object in the hangar. It smothersfire protection system embodying this invention in one of the hangars ofFig. 1.

In the drawings, wherein for the purpose of illustration is shown thepreferred embodiment of this invention, and particularly referring toFig. 1, the reference character 5 designates each one of a series offour hangars which may be considered as representative of the hangarequipment of a large commercial airport or a flying field. It is to beunderstood that these hangars are, as is the conventional practice,suitably spaced from each other to provide protection against the spreadof fire from one hangar to the other. The reference character 6designates a runway which may be considered as representative of thesystem of runways provided at all upto-date flying fields. The runwaysusually are spaced or located a sufi'icient distance from all rangars,or other buildings, so that the buildings will in no way interfere withthe maneuvering of planes while landing or taking olf. It will beunderstood that Fig. 1 is a condensed illustration of a flying field anddoes not accurately depict the relative position of airport hangars andrunways.

As is illustrated in Fig. 2, modern hangars are usually constructed'withside walls 7 which are formed of any suitable fireproof material, suchas reinforced concrete, hollow tile, or the like. The opposite ends ofthe hangar are usually closed ,by sectional doors 8. The varioussections of these doors may be either slidably mounted on runways sothat they may be moved into their open and closed positions or thevarious sections may be hingedly connected so that they may be foldedback or to the side, as is illustrated at 9 in Fig. 1. Regardless ofwhat type of door structure is employed, the design will be such thatthe entire width of the hangar will be left unobstructed when the doorsare arranged in their fully open position. A suitable fireproof roofcovering 10 is supported by steel trusses or rafters ll which aresupported at their opposite ends on the side walls 1. No intermediatesupport is provided for the roof rafters because it is essential thatthe entire interior of the hangar be left 1mobstructed to allow forhandling the planes housed therein.

As it is the primary purpose of the fire extinguishing system embodyingthis invention to provide maximum protection for the several hangars,the system is intended to provide ample liquid carbon dioxide to totallyflood at one time any one of the several hangars. Of course, all of thehangars at any airport or other flying field or the several hangars tobe found at different flying fields cannot each be expected to requirethe same amount of liquid carbon dioxide to provide total flooding. Anyfigures given herein, therefore, should only be considered as exemplaryand should not be treated as critical or as in any way limiting theinvention. As an aid in explaining the fire extinguishing systemembodying this invention, it will be considered that the airportrepresented by the disclosure of Fig. l is the commercial airportreferred to above. Therefore, each one of the four hangars designated bythe reference character may be considered as requiring 80 tons of liquidcarbon dioxide, maintained at a subatmospheric temperature and itscorresponding vapor pressure, to totally flood the same with carbondioxide vapors at a concentration of at least 30%. With the hangars 5spaced from each other a reasonable distance and with a major fire to beextinguished by the flooding of the involved hangar with carbon dioxidevapors, full protection for all of the hangars can be provided bymaintaining in the entire system suflicient liquid carbon dioxide tototally flood only one hangar. For this particular example, therefore,the minimum storage capacity of the entire fire extinguishing systemwill be 80 tons of liquid. However, as the carbon dioxide is to beexpelled or discharged from the system under its own vapor pressure, acertain amount of vapor will always remain in the storage tanks andpiping and an allowance should be made to provide the required 80 tonsin excess of the vapors which will remain after the system istheoretically exhausted. As the entire system, when filled, will containa very high percentage of liquid, there being only small vapor spacesprovided in each one of the storage tanks, the total capacity of thepiping of the system will provide enough liquid to produce the residualvapor charge after the system is exhausted of its available liquid. Itcan be considered, therefore, that the total storage capacity of thetanks should at least equal the minimum requirements of the system.Therefore, the total storage capacity of the insulated tanks l2 shouldbe tons, or enough liquid carbon dioxide to totally flood any one of thehangars 5. With this requirement for the total storage space, each tankl2 may have a minimum capacity of 20 tons. Of course, each one of thesestorage tanks I 2 may have a greater capacity than 20 tons if it isdesired to provide the system with a greater amount of liquid carbondioxide than is actually necessary to flood a single hangar. Forexample, each one of the tanks l2'might be the equivalent of one of therailway tank car tanks referred to above and have a capacity of 24 tons.It will be appreciated, also, that the 20 ton storage capacity of eachone of the tanks l2 may be split up into smaller units by th provisionof two or more tanks for each hangar. Each tank, and the entire system,may be charged with liquid carbon dioxide by means of the fillingconnections l3,

To apply the fire extinguishing method of my aforesaid patent to thissystem, the tanks, etc., should be charged with liquid carbon dioxide ata desired subatmospheric temperature and pressure The expressionsubatmospheric temperature is intendedto cover any desired, selectedtemperature below a normal atmospheric temperature of 70 F. After theentire system is charged with liquid carbon dioxide, the temperature ofthe liquid is to be maintained at a desired low value. This value willusually fall between 0 F. and 40 F. This subatmospheric temperature ismaintained by means of a conventional, commercial refrigerating unitwhich is diagrammatically illustrated at It. One of these units will beprovided for each storage tank l2. The refrigerating machine i4 isconnected by the necessary piping IE to a cooling coil located in theassociated tank I2. As has been disclosed in my aforementioned patent,the most economical arrangement is to provide a cooling coil within thevapor space of the tank l2. As a precaution against the failure of arefrigerating machine It, each tank may be provided with a slowbleed-off valve which is diagrammatically illustrated at Hi. This valvewill function to bleed off carbon dioxide vapors if the refrigeratormachine It fails and the vapor pressure rises above a given value withinthe storage tank l2. As the bleeding of carbon dioxide vapors from atank will result in self-cooling of the remaining liquid in the tank,the various valves 5 will function by themselves to maintain the liquidin the system at a desired subatmospheric temperature, and itscorresponding vapor pressure, in the absence of the operation of any ofthe refrigerating machines I i. As is illustrated in the figures, thevarious storage tanks l2 are interconnected by pipe lines ll. These pipelines are connected at their ends to the liquid spaces of the tanks I2and are located at a lower level than the tanks, These pipe lines H areto be maintained in open communication with the tanks at all times withthe result that the pipes I! will always be filled with liquid carbondioxide. Any vapors which may be formed in these pipes as a result ofabsorption of heat will pass through the liquid in the pipes and willpercolate through the liquid in the storage tanks 12 to reach the vaporspaces of said tanks. The pipes therefore, can be considered as "wetpipes and as containing columns of liquid carbon dioxide whichinterconnect the several tanks. With this type of connection between theseveral tanks I2, it will be possible to start drawing otf the liquidfrom any one of the tanks and to continue the discharge of liquid,without any interruption, until all of the tanks are exhausted of theiravailable liquid, leaving only a residual charge of vapor in the entiresystem. The object of dividing the total storage into separate unitswith one unit closely associated with each hangar is to make it possibleto start the discharge of the extinguishing medium into any one of thehangars immediately upon the discovery of a serious fire or theactuation of any suitable, automatic control mechanism which will beresponsive to a sudden rise in temperature within a hangar. No attempthas been made to illustrate either a manual or an automatic type ofcontrol system for the illustrated extinguishing system asanyconventional controls may be employed as desired.

The discharge of the carbon dioxide vapor into the hangar isaccomplished by means of a pipe line I9 which extends to and up one sidewall I to enter the hanger in the vicinity of the roof ID. This pipeline I9 then branches out into two interconnected manifold pipes 20.These manifold pipes may be provided with any desired number of branches2I. A suitable discharge nozzle 22 will be attached to each branch 2|.Fig. 2 discloses these discharge nozzles 22 as being arranged to directthe liberated carbon dioxide, which will take the form of a mixture ofvapor and snow, through the area occupied by the roof rafters or trussesI I. As this discharging cloud of vapor and snow has a subzerotemperature, the rafters will be maintained at a low temperature andthere will be no danger of them buckling or warping and permitting theroof I to collapse into the hangar.

To dispense with any need for portable fire extinguishers to take careof small, localized fires in and around the hangars and fires resultingfrom crashes on the runways, this system includes any desired number ofhose lines which may be located at suitable strategic points. As anexample of a suitable arrangement of such hose lines, Fig. 1 illustratesthree hose reels 23, 24, and 25 for each hangar. These hose reels areprovided with any suitable length of hose 26 which may be run off of thereels. A suitable nozzle 2'! is provided at the discharge end of eachhose. It will be noted that the reels 24 are located in a pit 28 beneaththe floor of their respective hangars. provided for covering these pitswhen the hose lines are not needed. The reels 25 are located in pits 39formed in the runway 6. These pits, also, will be suitably covered sothat they will not interfere in any way with planes using the runway.Branch lines 3| connect the sections of hose 26 on the reels 23 to theassociated storage tanks I2. The hose 26 on the reels 24 are connectedto the pipe lines I9 by branch lines 32. Of course, suitable valvemechanism will be provided for permitting the extinguishing medium to bedischarged through the hose lines 26 without being discharged throughthe nozzles 22. The hose lines 26 mounted, on reels 25 are supplied withcarbon dioxide from their respective tanks I2 by means of branch lines33. It will be appreciated that a small fire starting in the rearportion of any one of the hangars may be extinguished by use of a hoseline 26 and that Suitable cover plates may be any small fire starting inthe front portion of a hangar may be extinguished by using the hose line26 on the reel 23. If an attempt is made to extinguish a small fire in ahangar by means of a hose line and the fire gets beyond control, thecarbon dioxide discharged through the hose line will not be wasted andwill help to flood the hangar if it becomes necessary to discharge allof the carbon dioxide stored in the system to effect complete floodingof the hangar.

It will be understood that any suitable number of valves may be employedand located at any desired points for controlling the discharge ofcarbon dioxide through the several hose lines. Also, the branch lines3|, 32, and 33 either may be kept dry or wet as desired. In other words,these branch lines may either be kept filled with liquid carbon dioxideup to suitable control valves located adjacent the hose reels,

or the supply of liquid carbon dioxide may be shut oif from these branchlines back at the respective storage tanks I2. No attempt has been madeto illustrate suitable locations for the control valves.

Although the drawings disclose the storage tanks I2 and therefrigerating machines I4 as being located outside of the hangars andabove the surface of the ground, it will be understood that thesedevices, also, may be located inside the hangars or they may be locatedbelow the surface of the ground either outside the hangars or beneaththe floors of the same. Therefore, such terms as the immediate vicinity"of the hangars and located adjacent each hangar are not to be construedas limiting the location to that which is actually illustrated but areto be construed as covering such additonal locations as those mentionedabove.

It is to be understood that the form of this invention herewith shownand described is to be taken as a preferred example of the same, andthat various changes in the shape, size, and arrangement of parts may beresorted to without departing from the spirit of the invention or thescope of the subjoined claims.

Having thus described the invention, I claim:

1. A method of extinguishing a fire in any one of a plurality of hangarsat a commercial airport, or flying field, comprising maintaining in bulkstorage in the immediate vicinity of each one of the involved hangars afractional portion of the entire quantity of liquid carbon dioxide to beused in the extinguishment of a fire, maintaining all of the storedfractional portions of liquid in open communication with each other sothat the entire quantity of liquid will be available for continuousdischarge into any one of the hangars, and discharging into the hangarin which the fire is burning a sufiicient amount of the entire quantityof stored carbon dioxide to effect total flooding of the interior of thehangar with carbon dioxide vapor.

2. A method of extinguishing a fire in any one of a plurality of hangarsat a commerc al a rport, or other flying field, comprising maintainingin bulk storage in the immediate vicinity of each one of the involvedhangars a quantity of liquid carbon dioxide, at a substantially constantsubatmospheric temperature and its correspond ng vapor pressure, whichis only a fractional portion of the entire amount of liquid carbondioxide to be used in the extinguishment of a fire, maintaining all ofthe stored fractional portions of the liquid in open communication witheach other so that the entire quantity of liquid will be available forcontinuous discharge into any one of the hangars, and discharging intothe hangar in which the fire is burning a sufiicient quantity of thestored carbon dioxide to effect total flooding of the interior of thehangar with carbon dioxide vapors.

3. A method of extinguishing a fire-in any one of a plurality of hangarsat a commercial airport,

or other flying field, comprising maintaining in bulk storage in theimmediate vicinity of each one of the involved hangars a, fractionalportion of the entire quantity of liquid carbon dioxide to be used inthe extinguishment of the fire, maintaining all of the stored fractionalportions of liquid in open communication with each other so that theentire quantity of stored liquid willbe available for continuousdischarge into any one of the hangars, and discharging into the hangarin which the fire is burning all of the entire quantity of carbondioxide stored at the several hangars which can be dischargedunder itsown vapor pressure.

4. A method of extinguishing a fire in any one of a plurality of hangarsat a commercial airport, or other flying field, comprising maintainingin bulk storage in the immediate vicinity of each one of the involvedhangars a fractional portion of the entire quantity of liquid carbondioxide to be used in the extinguishment of a fire, maintaining all ofthe stored fractional portions of liquid in open communication with eachother so that the entire quantity of stored liquid will be available forcontinuous discharge into any one of the hangars, and discharging intothe hangar in which the fire is burning a sufiicient amount of theentire quantity of stored carbon dioxide to provide a carbon dioxidevapor concentration in the hangar of at least 30%.

5. A method of extinguishing a fire in any one of a plurality of hangarsat a commercial airport, or other flying field, comprising maintainingin bulk storage in the immediate vicinity of each one of the involvedhangars a quantity of liquid carbon dioxide, at a substantially constantsubatmospheric temperature and its corresponding vapor pressure, whichis only a fractional portion of the entire amount of liquid carbondioxide to be used in the extinguishment of a fire, maintaining all ofthe stored fractional portions of liquid in open communication with eachother so that the entire quantity of stored liquid will be available forcontinuous discharge into any one of the hangars, and discharging intothe hangar in which the fire is burning all of the entire quantity ofcarbon dioxide stored at the several hangars which can be dischargedunder its own vapor pressure so as to provide a carbon dioxide vaporconcentration of at least 30% in said hangar.

6. A fire extinguishing system for commercial airports, or other flyingfields, each of which has a plurality of hangars, comprising aninsulated storage container of several hundred pounds capacity locatedadjacent each hangar, means operatively connected to each container formaintaining liquid carbon dioxide stored therein at a selectedsubatmospheric temperature and its corresponding vapor pressure, pipinginterconnecting the liquid spaces of all of the containers and beingarranged at a lower level than the same so as to be maintained filledwith liquid carbon dioxide and to allow any vapors which may formtherein to rise into one or more of the containers, and means connectedto each container for discharging into its adjacent hangar any desiredportion oihthe total amount of liquid stored in that container and allof the other containers.

7. A fire extinguishing system for commercial airports, or other flyingfields, each of which has a. plurality of hangars, comprising a storagecontainer of several hundred pounds capacity located adjacent eachhangar, piping interconnecting the liquid spaces of all of thecontainers and being in open communication therewith for maintaining thepiping filled with liquid carbon dioxide and for allowing any vaporswhich may form therein to rise into said containers, and means connectedto each container for discharging into its adjacent hangar any desiredportion of the total amount of liquid stored in that container and allof the other containers.

8. A fire extinguishing system for commercial airports, or other flyingfields, each of which has a plurality of hangars, and a runway common toall of said hangars, comprising an insulated storage container ofseveral hundred pounds capacity located adjacent each hangar, meansoperatively connected to each container for maintaining the liquidcarbon dioxide stored therein at a selected subatmospheric temperatureand its corresponding vapor pressure, piping "interconnecting the liquidspaces of all of the containers and being in open communicationtherewith for maintaining the piping filled with liquid carbon dioxideand for allowing any vapors which may form therein to rise into the saidcontainers, means connected to each container for discharging into itsadjacent hangar any desired portion of the total amount of liquid storedin that container and all of the other containers, a plurality ofcovered pits formed at suitably spaced points along said runway, a hoseline having a discharge nozzle positioned in each of said pits, andpiping for connecting each one of said hose lines to an adjacent storagecontainer.

9. A fire extinguishing system for commercial airports, or other flyingfields, each of which has a plurality of hangars and a runway common to1 all of said hangars, comprising a storage container of several hundredpounds capacity located adjacent each hangar, piping interconnecting theliquid spaces of all of the containers and being arranged at such alevel relative to said containers as to be maintained filled with liquidcarbon dioxide and to allow any vapors which may form therein to riseinto one or more of the containers, means connected to each containerfor discharging into its adjacent hangar any desired portion of thetotal amount of liquid stored in that container and all of the othercontainers, a plurality of covered pits formed at suitably spaced pointsalong said runway, a hose line having a discharge nozzle positioned ineach one of said pits, and piping for connecting each one of said hoselines to an adjacent storage container.

10. A fire extinguishing system for commercial airports, or other flyingfields, each of which has a plurality of hangars, comprising aninsulated storage container of several hundred pounds capacity locatedadjacent each hangar, means operatively connected to each container formaintaining liquid carbon dioxide stored therein at a selectedsubatmospheric temperature and its corresponding vapor pressure, pipinginterconnecting the liquid spaces of all of the containers and being inopen communication therewith so as to be maintained filled with liquidcarbon dioxide and to allow any vapors which may form therein to riseinto the containers, a piping system extending from each container intothe adjacent hangar and terminating in a pluralityof outlets adjacentits roof, and a discharge nozzle for each outlet arranged to direct theextinguishing medium discharged therefrom in the direction of the roofrafters of the hangar.

11. A fire extinguishing system for commercial airports, or other flyingfields, each of which has a plurality of hangars, comprising a storagecontainer of several hundred pounds capacity located adjacent eachhangar, piping interconnecting the liquid spaces of all of thecontainers and being arranged at such a level relative to saidcontainers as to be maintained filled with liquid carbon dioxide and toallow any vapors which may form therein to rise into the containers, apiping system extending from each container into the adjacent hangar andterminating in a plurality of outlets adjacent its roof, and a nozzlefor each outlet arranged to direct the extinguishing medium dischargedtherefrom in the direction of the roof rafters of the hangar.

12. A fire extinguishing system for commercial airports, or other flyingfields, having a hangar, comprising an insulated storage container ofseveral hundred pounds capacity located outside of but adjacent saidhangar, means operatively connected to said container for maintainingliquid carbon dioxide stored therein at a selected subatmospherictemperature and its corresponding vapor pressure, a piping systemextending from the container into the hangar and terminating in aplurality of outlets adjacent its roof, and a nozzle for each outletarranged to direct the extinguishing medium discharged therefrom in thedirection of the roof rafters of the hangar.

13. A fire extinguishing system for commercial airports, or other flyingfields, having a hangar, comprising a storage container of severalhundred pounds capacity located outside of but adjacent to said hangar,a piping system extending from said container and entering the hangaradjacent its roof, said piping system terminating within the hangar in aplurality of outlets adjacent the roof, and a nozzle for each outletarranged to direct the extinguishing medium discharged therefrom in thedirection of the roof rafters of the hangar.

14. A fire extinguishing system for commercial airports, or other flyingfields, having a runway for the landing and taking ofi of planes,comprising a plurality of bulk storage containers spaced along therunway, piping interconnecting the liquid spaces of all of thecontainers and being in open communication therewith for maintaining thepiping filled with liquid carbon dioxide and for allowing any vaporswhich may form therein to rise into said containers, a plurality ofcovered pits formed at suitably spaced points along said runway, a hoseline having a discharge nozzle positioned in each one of said pits, andpiping for connecting each hose line to the closest bulk storagecontainer and through said interconnecting piping toall of the othercontainers.

15. A fire extinguishing system for an airplane hangar, or the like,comprising a carbon dioxide storage system of sufficient capacity toeffect total flooding of the hangar and including an insulated storagecontainer holding a part of the entire charge and being located adjacentthe hangar so that its contents will be available for immediate deliveryto the hangar, a piping system extending from the container into theadjacent hangar and terminating in a plurality of outlets adjacent itsroof, and a discharge nozzle for each outlet arranged to direct thecarbon dioxide discharged therefrom in' the direction of the roofrafters of the hangar.

16. A method of extinguishing a fire in any one of a plurality ofhangars at a commercial airport, or flying field, comprising maintainingin bulk storage in the immediate vicinity of each one of the involvedhangars a fractional portion of the entire quantity of liquid carbondioxide to be used in the extinguishment of the fire, maintaining all ofthe stored fractional portions of the liquid in open communication witheach other so that the entire quantity of liquid will be available forcontinuous discharge into any one of the hangars, and discharging intothe hangar in which the fire is burning, and adjacent the roof thereofso as to maintain the roof rafters at a low temperature to preventfailure of the same, a suflicient amount of the entire quantity ofstored carbon dioxide to eflect total flooding of the interior of thehangar with carbon dioxide vapors.

17. A method of extinguishing a fire in any one of a plurality ofhangars at a commercial airport, or other flying field, comprisingmaintaining in bulk storage in the immediate vicinity of each one of theinvolved hangars a quantity of liquid carbon dioxide,. at asubstantially constant subatmospheric temperature and its correspondingvapor pressure, which is only a fractional portion of the entire amountof liquid carbon dioxide to be used in the extinguishment of a fire,maintaining all of the stored fractional portions of the liquid in opencommunication with each other so that the entire quantity of liquid willbe available for continuous discharge into any one of the hangars, anddischarging into the hangar in which the fire is burning, and adjacentthe roof thereof so as to maintain the roof rafters at a low temperatureto prevent failure of the same, a sufficient quantity of the storedcarbon dioxide to effect total flooding of the interior of the hangarwith carbon dioxide vapors.

18. A method of extinguishing a fire in an airplane hangar, or the like,comprising maintaining in bulk storage a suflicient quantity of liquidcarbon dioxide to effect total flooding of the interior of the hangarwith carbon dioxide vapors, a fractional portion of said quantity beingstored in the immediate vicinity of said hangar while the remainder isremotely located with respect to said hangar, maintaining the separatelystored portions of the entire quantity of liquid in open communcationwith each other so that the entire quantity of liquid will be availablefor continuous discharge into the hangar, and discharging into thehangar, when a fire occurs, a suflicient amount of the entire quantityof stored carbon dioxide to effect extinguishment of the fire by vaporflooding.

19. A method of extinguishing a fire in any one of a plurality ofhangars at a commercial airport, or flying field, comprising maintainingavailable for immediate use in the immediate vicinity of each one of theinvolved hangars a fractional portion of the entire quantity of liquidcarbon dioxide to be used in the extinguishment of a fire in any hangar,maintaining all of the stored fractional portions of the liquid in opencommunication with each other so that the entire quantity of liquid willbe available for continuous discharge into any one of the hangars, anddischarging into the hangar in which the fire is burning a sufficientextinguishing a, fire, maintaining all of the stored fractional portionsof liquid in open communica-- tion with each other so that the entirequantity of liquid will be available for immediate and continuousdischarge in each one of the areas served by said several storedfractions, and eflecting discharge onto the fire consuming an airplaneon o the field a sumcient amount of the entire quantity of stored carbondioxide to efiect the desired extinguishment.

21. A fire extinguishing system for commercial airports, or other flyingfields, each of which has a plurality of hangars, comprising a storagecontainer of several hundred pounds capacity located adjacent eachhangar, piping interconnecting the liquid spaces of all of thecontainers and being in open communication'therewlth for maintaining thepiping filled with liquid carbon dioxide and for allowing any vaporswhich may form therein to rise into said containers, and a plurality ofdevices capable of effecting a fire extinguishing discharge of carbondioxide in and around each hangar and connected to their particularhangar container, and all of the other containers through saidinterconnecting piping, for discharging any desired portion of the totalamount of liquid stored in all of the containers. ERIC qEER'rz.

